Flashcards in Biol 441 exam 2 Deck (21)
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1
Curie's principle
Effects have the same symmetry as their causes (and sometimes more)
2
Fucus brown alga symmetry breaking
Roots sprout on the darker side of the cell at the spherical 1 cell stage
3
Frog/salamander symmetry breaking
Point of sperm entry determines anterior-posterior (or dorsal-ventral) axis
4
Notochord is replaced by (in mammals and birds)
vertebral column
5
Notochord geometry
Stacked, inflated coins with large vacuoles
6
Notochord movement capabilities
Bending side to side
No anterior-posterior compression
7
Notochord convergent extension
Notochord cells extend processes sideways
They attach to each other and contract, stretching itself out
8
Notochord cells in reptiles, birds, and mammals
Last to leave the surface of the embryo, the epiblast, at Hensen's Node
9
Somite formation location
Beside the neural tube at the paraxial mesoderm
10
Theories of somite splitting (2)
Active constriction
Decrease of cell-cell adhesion
11
Progenitor somites
Somitomeres
12
Theories of somite signalling (2)
Genetic mechanism similar to fly segmentation (Hox genes)
"Clock and wavefront" hypothesis
13
Somite subdivisions (4)
Dermatome
Myotome
Anterior sclerotome
Posterior sclerotome
14
Lateral plate mesoderm layer divisions (2)
Splanchnic layer
Somatic layer
15
Space in-between 2 layers of LPM
special feature in reptiles, birds, and mammals
Coelomic cavity
filled with coelomic fluid
in reptiles, birds, and mammals, is continuous with the space in-between the chorion and amnion, called the extraembryonic coelom
16
Heart development location
Where the 2 sides of the LPM meet
17
Heart development if barrier blocks joining of LPM
2 normally functioning hearts
18
PGC origin in birds
Crescent shaped area of extra-embryonic tissue in front of head
19
PGC origin in flies and nematodes
The rearmost part of the embryo
Determined by special pre-positioned granules
20
PGC origin in mammals and amphibials
Extreme ventral endoderm
21
